Conventionally, it is known to perform preliminary air-conditioning in vehicle and a vehicle air conditioner is started before the driver or passenger (hereinafter referred to the driver) enters the vehicle. For example, preliminary air-conditioning is described in Japanese Patent Publication No. 3,287,110.
Preliminary air-conditioning is frequently performed in the summer. The air conditioner is operated, by receiving the starting signal from a driver's transmitter, to lower the temperature of the cabin to a comfortable level by the time the driver enters the vehicle.
In order to make the cabin temperature comfortable, it is necessary to strongly cool the cabin for a long time. When the interval from the air-conditioner starting time to the driver entering time is short, interior equipment such as a steering wheel, a seat and so on can still be hot. Therefore, when the driver enters the vehicle, contact with hot interior equipment may make him uncomfortable. Furthermore, the temperature of the instrument panel be reduced easily and the radiant heat emitted from the instrument panel can undesirably affect the driver.